Morphological and Chemical Correlations in the Cladonia chlorophaea Complex

Abstract

Measurements of granules from within the podetial cups of different chemical variants of the Cladonia chlorophaea complex in North Carolina show clear correlation between granule size and certain chemical characters. The results support the view that the replacement of cryptochlorophaeic acid by grayanic acid in this group is taxonomically more significant than the presence or absence of fumarprotocetraric acid. In the species tested, the soredia of C. conista are the smallest, those of C. perlomera and C. grayi are intermediate, and those of C. cryptochlorophaea are the largest. The Cladonia chlorophaea group was treated by Sandstede (1931) as including two species-C. chlorophaea (Flirke) Spreng., containing fumarprotocetraric acid and consequently distinguished by a bitter taste, and C. grayi Merr. ex Sandst., lacking fumarprotocetraric acid and consequently with a mild taste. Asahina (1940) discovered grayanic acid, cryptochlorophaeic acid, and merochlorophaeic acid in this group and divided the complex into four species: Cladonia grayi, C. cryptochlorophaea Asah., and C. merochlo?rophaea Asah. are characterized by the presence of grayanic acid, cryptochlorophaeic acid, and merochlorophaeic acid, respectively, while C. chlorophaea is considered to have fumarprotocetraric acid only. Within each of the first three species, the presence or absence of fumarprotocetraric acid is generally ignored from taxonomic considerations, but Asahina treated such fumarprotocetraric acid variants as forms. Although these four species are the most common ones of the chlorophaea group, many other variants have been recorded (Ahti, 1966; Culberson & Kristinsson, 1969). The morphologic variability has generally been considered to be the same within all the chemically different races in the complex. Ahti (1966), however, indicated some morphological differences between some of the plants called C. merochlorophaea and those of the other chemical species, and Krog (1968) claimed that the rangiformic acid variant in Alaska has a characteristic morphology. Wetherbee (1969) has demonstrated substrate specificity in some of the chemical species in Michigan. The present paper deals with the morphology and distribution of the chemical variants of the C. chlorophaea group in North Carolina. Since a preliminary survey indicated that there was a significant difference in the size of the soredia in the podetial cups between some of the chemical variants, a large-scale survey was made. Other 1 This study was supported by grant GB-6041X from the National Science Foundation. I thank Dr. William Louis Culberson for his interest in this work and for linguistic corrections and Dr. Chicita F. Culberson for her advice on the identification of the lichen substances. 2 Department of Botany, Duke University, Durham, North Carolina 27706. Present address: NMttlirugripasafnit Q Akureyri, P.O. Box 580, Akureyri, Iceland. This content downloaded from 157.55.39.153 on Mon, 19 Sep 2016 04:46:55 UTC All use subject to http://about.jstor.org/terms 14 THE BRYOLOGIST [Volume 74 100 Cladonia grayi PD+ s ---C. grayi PD?. C. cryptochlorophaea PD+ . .... .. ........ C. cryptochlorophaea PDo/ .... C)' I 0 100 200 300p LLI N A